There were also clock speed selectors that really did let the CPU run faster. They would let you switch to a CPU clock speed that was higher than the speed the

There were also clock speed selectors that really did let the CPU run faster. They would let you switch to a CPU clock speed that was higher than the speed the CPU was originally rated for. The cost was a greater possibility of crashes. Depending on what you were doing and how stable the CPU was it was a noticeable improvement. Some selectors would let you choose between 2 speeds, others had multiple speed selections. Often the higher ones would crash a lot more. There were also variable speed controls that acted like a rheostat with continuous speed changes. Those worked but were even more unstable.